[sdiy] semi-OT: USB cable shield

[Neil Johnson]

Hi,

Ingo Debus wrote:
> as far as I know, the shield of USB connectors usually is connected directly
> to ground. However I've seen designs where there's a smallish capacitor (10
> nF) in parallel with an 1 megohm resistor between the housing of the USB
> receptacle and ground. Why is this?

To control RFI.

http://www.ti.com/sc/docs/apps/msp/intrface/usb/emitest.pdf

Neil
--
http://www.njohnson.co.uk